Process for continuously dyeing wool fibers with mordant black 11 and treating with sodium nitrite

ABSTRACT

A PROCESS FOR THE CONTINUOUS DYEING OF POLYAMIDE FIBERS COMPRISING APPLYING TO SAID FIBERS AN AQUEOUS SOLUTION OF A NON-CATIONIC DYESTUFF, A THICKENER, ACID SUFFICIENT TO ADJUST THE PH OF THE SOLUTION TO ABOUT 2 TO ABOUT 5, A TRIVALENT CHROMIUM COMPOUND, A DYESTUFF CARRIER IN WHICH THE DYESTUFF IS SOLUBLE, STEAM FIXING THE DYESTUFF ON THE FIBERS AND WASHING THE DYED FIBERS, THAT IS IMPROVED BY TREATING THE DYED FIBERS AFTER STEAM FIXING BUT BEFORE WASHING WITH AN AQUEOUS SODIUM NITRITE SOLUTION.

United States Patent 3,597,144 PROCESS FOR CONTINUOUSLY DYEING WOOL FIBERS WITH MORDANT BLACK 11 AND TREATING WITH SODIUM NITRITE John A. Leddy, Hawthorne, N.Y., assignor to Geigy Chemical Corporation No Drawing. Continuation-impart of application Ser. No. 584,684, Oct. 6, 1966. This application Oct. 13, 1969, Ser. No. 866,037

Int. Cl. D061) 5/02 U.S. Ci. 874 11 Claims ABSTRACT OF THE DISCLOSURE A process for the continuous dyeing of polyamide fibers comprising applying to said fibers an aqueous solution of a non-cationic chrome dyestuff, a thickener, acid sufficient to adjust the pH of the solution to about 2 to about 5, a trivalent chromium compound, a dyestuff carrier in which the dyestufi is soluble, steam fixing the dyestulf on the fibers and washing the dyed fibers, that is improved by treating the dyed fibers after steam fixing but before washing with an aqueous sodium nitrite solution.

CROSS REFERENCES TO RELATED APPLICATIONS This application is a continuation-in-part application of my copending application Ser. No. 584,684 filed Oct. 6, 1966, now abandoned.

THE INVENTION This invention relates to an improvement in the continuous dyeing of polyamide fibers and in particular, Wool.

A continuous dyeing process as opposed to batch dyeing processes produces dyed fibers of superior color fastness and fibers almost entirely free from chemical and physical degradation as a result of the dyeing process.

Besides the aforementioned advantages of continuous dyeing, this continuous process permits the dyeing of Wool or synthetic polyamide fibers in a wide pH range em bracing acid pH values as low as 2. This permits the use of a wide selection of dyes, including chrome dyes. Of particular significance is the possibility of continuously dyeing wool tops for use in mens worsted blends with a chrome dye.

Wool blends in which a portion of the blend is wool which has been dyed black previous to the blending operation comprise a significant portion of the market for dyed wool.

Conventional dyeing methods yield dyed fibers which in general are deleteriously affected by the dyeing process itself. In conventional dyeing, the dye liquor is pumped through the fibers for relatively long periods of time. The fibers are also subjected to a considerable amount of physical handling which results in the formation of neps, crossovers, and distortion.

Furthermore, since the dyeing operation according to the continuous process exposes the fibers to the padliquor for a much shorter time as opposed to conventional methods, the fibers are not adversely affected by exposure to extreme acid conditions for any substantial time period.

In the continuous dyeing process to which this inprovement relates and which is more fully described in copending application Ser. No. 525,937, filed Feb. 8, 1966, now US Pat. 3,503,698 issued Mar. 31, 1970, the dye liquor is padded onto the fibers, such as wool tops, and the dye in the fiber is steam fixed thereon in a relatively short period of time, and then the dyed fibers are washed.

This continuous process is made possible by new improved dye carriers described in the aforementioned patent ice application and is conveniently carried out in machinery such as described in Belgian Patent 641,637, filed Oct. 20, 1964 to Ilma, S.A., Schio, Italy.

More particularly, the continuous process, with which the improvement of this invention is concerned, comprises impregnating polyamide fibers with an aqueous pad-liquor which contains, as essential constituents, an amount of 5 to 10 grams, and preferably 20 to grams, per liter of liquor, of the dyestufi' carrier defined in detail below; a non-cationic chrome dyestutf capable to drawing on the fibers from a pad-liquor of a pH ranging from 2 to 5; and optionally, but preferably, as a clarifying agent, a lower alkanol, of preferably 3 to 4 carbon atoms, especially isopropanol or of fi-alkoxyethanol having a total of from 3 to 8 carbon atoms, such as B-methoxyethanol, fl-ethoxyethanol or S-hexoxyethanol, or mixtures of isopropanol and the aforesaid alkoxy-ethanols.

The impregnation of the fibers is carried out at a temperature below the drawing temperature of the respective dyestuffs being used, and at a pH of about 2 to 5. The dyestuff is fixed in the treated goods by a heat treatment in a humid medium, preferably without intermediate drying, by treating the goods with hot steam; and finally washing the dyed fibers.

Where it is desirable to employ chrome dyes in the dyeing of polyamide fibers according to this continuous process, it previously has not been possible to achieve an extremely high degree of apparent fastness which is, of course, most desirable. This is now attainable through the utilization of the new improvement of this invention. This is particularly important in the case of the dyeing of wool tops with a chrome dye such as Color Index Mordant Black 11, Color Index No. 14645, which is widely used in preparing blended fabrics.

It is extremely important for example that the wool tops used for the mens goods market, such as worsted blends, possess a very high degree of fastness in order to prevent a dulling effect on the finished blend and/or loss of depth and shade.

The lack of actual fastness or apparent fastness of dyes is readily determined by well-known AATTS tests. The lack of fastness manifests itself in shade changes in the dyed fabric and various degrees of staining of fabrics which are blended with the wool.

The improvement of this invention comprises the use in the foregoing continuous process of trivalent chromium salts, preferably chromic fluoride, as dye-fixing agents and the after-treatment of the dyed fiber in the washing cycle, with a sodium nitrite solution prior to a clear water wash. Optionally, a Wash with sodium acetate solution may be included after the washing with the sodium nitrite solution.

The dyestuff carrier which is essential for the successful carrying out of the above continuous dyeing process essentially consists, in one embodiment, of a mixture of (i) A sulfated condensation product of an alkanol of 8 to 14 carbon atoms with ethylene oxide or propylene oxide in molar ratios of from 1 to 20; the terminal hydroxy group of the condensation product being sulfated; and

(ii) A sulfated condensation product of higher alkylphenol with ethylene oxide or propylene oxide in molar ratios of 1 to 20; the terminal hydroxy group of the condensation product being sulfated; and

(iii) Salts of i and ii, preferably alkali metal, ammonium,

lower alkyl-ammoni'um or w-hydroxy-lower-alkyl-ammonium.

The ratio of the amides defined in (A) to the condensation products of (B), ranges from about :1 to 1:5, preferably 2:1 to 1:2, and ideally 3 :2 to 1:15.

A clarifying agent is preferably included in the mixture of (A) and (B) in order to insure the homogenity of the carrier mixture for a period of several months and even a year or more.

Such clarifying agent is a lower alkanol or a S-alkoxy ethanol, preferably being isopropanol. In the instances, where a clarifying agent is used, the proportion of (A) to (B) may range from about 2:1 to 1:2 and preferably 3:2 to 1:1.5, with the proportion of the clarifying agent ranging from about 4 to about by weight of the total weight of the carrier mixture.

In another modification, the dyestuif carrier of the above process may be comprised of a system consisting essentially of an unsulfated amide as defined in (A) above;

and

A sulfated hydroxy-lower alkyl substituted amide formed from an aliphatic monocarboxylic acid and a primary or secondary amine having at least one hydroxy-lower alkyl group.

The weight ratio of a sulfated compound of (C) to the unsulated compound of (A) in this instance is in the range of 5 :1 to 1:5 and preferably from 2:1 to 1:2.

The sulfated compounds defined under (C) are usually employed in the form of a soluble salt such as alkali, ammonium lower alkyl, or hydroxy-lower alkyl-ammonium. In the latter case, the dior tri-(B-hydroxyethylamine) salts are preferred. The clarifying agent defined above is also preferably included in the mixture of (A) and (C).

A further variation in the composition of the dyestuif carrier employed in this continuous dyeing process comprises a combination of an unsulfated amide as defined in (A) and a mixture of the sulfated compounds defined in (B) and (C) in which the ratio of (B) to (C) is in the range of from 5 :1 to 1:5, preferably in the range of 2:1 to 1:2.

Another modification of a dye carrier employed in the foregoing continuous dyeing process is a mixture of an unsulfated amide as defined in (A), and

A sulfated (alkylphenol) [2,3-dihydroxypropyl]ether, in which the alkyl radical has from 8 to 12 carbon atoms, and preferably 9 carbon atoms;

or a mixture of this sulfated ether with the sulfated amide defined in (C), or the soluble salts of these sulfated compounds.

Lower When used in the specification means that the radical referred to has from 1 to 4 carbon atoms.

The preferred composition of dye carrier and clarifying agent comprises a solution of diethanolamine salt of the sulfated diglycol ether of lauryl alcohol, coconut oil fatty acid dihydroxyethyl amide, and a mixture of isopropanol and 2-ethoxyethanol.

The combination of dye carrier and clarifying agent serves as a wetting agent, a solvent for the dyes, aids in the forming of a stable uniform solution of the dye, assists in the fixation of the dyestuffs, and exerts a blowing action on the wool tops which allows the steam to reach each individual fiber.

The individual components of the dyestutf carrier and clarifying agent are readily available from commercial 4 sources and/or produced by methods known to those skilled in the art.

The drawing temperature of the dyestuif used, that is, the temperature at which the dyestuif draws within about a minute upon the fiber, usually is 70 C. or above. Obviously impregnation of the fibers according to the continuous process should "be affected below the drawing temperature of the dyestufi.

It is the general object of this invention to provide an improved method of continuously dyeing polyamide fibers with chrome dyestuffs.

It is a particular object of this invention to make available an improved processs for continuously dyeing wool, such as wool tops with a chrome dye such as Mordant Black 11, Color Index 14645. The improved process of this invention results in a superior fastness of the dyed fibers which previously has not been attainable either wth known conventional dyeing processes or even the continuous dye ing processes recently made available in the art.

The impregnating solution is advantageously prepared by mixing warm aqueous dyestuif solutions or dispersions of suitable concentration, which contain thickeners, such as carob bean flour, galacto-mannan, tragacanth, dextrine, or locust bean gum, with the desired amount of carrierclarifier mixture, as defined hereinbefore, as well as, optionally, other additives familiar to those skilled in the art.

Acid is added to adjust the pH to from about 2 to about 5. Suitable acids which may be used are acetic, hydrochloric, formic, phosphoric, or any other one commonly used in the trade when chrome-dyeing polyamide fibers.

The polyamide fibers are impregnated advantageously at 30 to 70 C. and then squeezed out to the desired content of impregnating liquor which is abaut 40 to 130% and preferably to of the weight of the fiber.

The dye on the impregnated fiber is then steam fixed by treating the impregnated fibers with steam for from 10 to 40 minutes, and preferably about 30 minutes.

After the steaming step, the fibers are then Washed in an aqueous solution of sodium nitrite containing from about 1 to about 5, preferably 3 grams per liter of sodium nitrite. The sodium nitrite solution is preferably warm, for example, about 100 to about 212 F, with 160 F. being the preferred temperature. The dyed fibers may then be optionally washed in a sodium acetate solution containing about 3 grams per liter of sodium acetate, and then washed in plain water.

The latter two washings are preferably carried out at temperatures of about 160 F. and F. respectively.

The following examples describing the preferred embodiments of this invention will serve to further illus trate the nature of the invention. It is to be understood that the examples are merely illustrative and intended to enable those skilled in the art to practice the invention in all of the embodiments flowing therefrom and do not in any way limit the scope of the invention defined in the claims.

Example I A solution of approximately 40 grams of Mordant Black 11, Color Index No 14645 dyestufi; 10 grams of Polygum 260 ttu'ckener (a modified locust bean gum); 25 grams per liter of a mixture comprising 10 parts of the diethanolamine salt of the sulfated diglycol ether of lauryl alcohol, 9.1 parts of the coconut oil fatty acid dihydroxyethyl amide, 2.3 parts isopropanol, 1 part 2-ethoxyethanol and 2.5 parts water; and 25 ml. of formic acid, and 25 ml. of CrF -3'H O; the balance of water, per liter was prepared.

Wool tops were impregnated with the pad-liquor so formed, and squezed out to a liquid content of 120% calculated on the dry weight of the wool fibers and thereafter steamed for approximately 30 minutes.

After the steam treatment, the dyed fibers were washed in a bath of sodium nitrite (3 grams of sodium nitrite per liter) at a temperature of about F. for about 1 minute. After the fibers were washed in the sodium nitrite solution, they were washed in a bath of sodium acetate (3 grams of sodium acetate per liter) at a temperature of about 160 F. for about 1 minute. Finally the dye fibers were washed in clear water twice at a temperature of about 140 F.

Example II The same procedure as Example 1 was followed except that the step of washing the fibers in a sodium nitrite solution was omitted.

The fibers dyed according to Examples I and II were subjected to the following color fastness tests with the results tabulated in the table below.

Example II I Acid perspiration-AATTC 15-1962:

Shade change 4-5 Bleed:

4-5 4-5 4-5 3-4 4 Acetate 1-5 Washing.AATTC 1-1957, Mill Test N o. 1:

Shade change 4-5 45 Bleed:

5 5 5 5 4 4-5 3 4 4 5 Acetate 4 4-5 Fulling.AATTC 2-1957, AATTC No. 1:

Shade change 4 4-5 Bleed:

5 5 4 4 4-5 5 Acid cross dye:

Shade change 4-5 5 Bleed Wool 2-3 5 Grocking.-AATIC 8-1964:

Wet 3 4 Dry 3-4 4-5 The Acid Cross-Dye Test is designed to test resistance to bleeding. The dyed wool fiber is braided with an equal amount of undyed Wool fiber so as to hold the specimen in close contact. The braided wool fiber is placed in an acid bath containing 2% on weight of braid oi Acetic Acid 56% and 10% on Weight of braid Glauber Salt. The bath is brought to 200 F. and maintained at this temperature for 1 hour. The test specimen is removed and rinsed in cold water. The test specimen is dried, alter which the braid is looosened. The dyed specimen is removed from the undyed wool fiber. The undyed wool fiber is rated for degree of staining using the AATTC chart for Measuring Transference of Color.

Results indicated in the foregoing table demonstrate that the dyed fibers treated with the sodium nitrite solution according to this invention result in the greatly improved end-product. The fibers dyed according to the continuous process utilizing the improvement of this 1nvention exhibit outstanding qualities of fastness when subjected to the most stringent of the tests commonly employed by those skilled in the art.

While the invention has been explained by detailed descripition of certain specific embodiments, it is understood that various modifications and substitutions can be made in any of them within the scope of the appended claims.

What is claimed is:

1. In a process for the continuous dyeing of wool fibers which process comprises applying to said fibers an aqueous solution comprising, Mordant Black 11, Color Index No. 14645, a mineral or organic acid sufiicient to adjust the pH of said solution to from about 2 to about 5, chromic fluoride and a dyestuif carrier at a temperature below the drawing temperature of said Mordant Black 11, Color Index No. 14645, said carrier comprisan unsulfated amide formed from a substantially saturated monocarboxylic acid having from 10 to 14 carbon atoms, or lower alkanoic acid which is substituted with a higher alkylphenoxy, wherein the higher alkyl has from 8 to 12 carbon atoms, and preferably 9 carbon atoms; or a mixture of substantially saturated fatty acids having an average number of carbon atoms above 10, and preferably 12 to 16 carbon atoms, and a primary or secondary amine containing at least one hydroxy-lower alkyl group, which may be etherified; and

(i) a sulfated condensation product of an alkanol of 8 to 14 carbon atoms with ethylene oxide or propylene oxide in molar ratios of from 1 to 20; the terminal hydroxy group of the condensation product being sulfated; and

(ii) a sulfated condensation product of higher alkylphenol with ethylene oxide or propylene oxide in molar ratios of 1 to 20; the terminal hydroxy group of the condensation product being sulfated; and

(iii) salts of (i) and (ii), preferably alkali metal,

ammonium, lower alkylammonium, or w-hydroxy-lower alkyl ammonium;

the ratio of (A) to (B) being from 5:1 to 1:5; or

and

a sulfated hydroxy-lower alkyl substituted amide formed from an aliphatic monocarboxylic acid and a primary or secondary amine having at least one hydroxylower alkyl group,

the ratio of (C) to (A) being from 5:1 to 1:5; or

(III) a mixture of (A) with a mixture of (B) and (C), the

ratio of (B) to (C) being from 5:1 to 1:5; or

a mixture of (A), and

a sulfated (alkylphenol) [2,3-dihydroxypropyl]ether, in which the alkyl radical has from 8 to 12 carbonv atoms, and preferably 9 carbon atoms; said Mordant Black 11, Color Index No. 14645 dyestuff being soluble in said carrier, steam fixing said dyestufi on said fibers by reducing said chromic fluoride, and washing the dyed fibers, the improvement which comprises treating said dyed fibers after said steamfixing, and before said washing, with an aqueous sodium nitrite solution, thereby improving the fastness of the dyed fibers.

2. The improvement claimed in claim 1 comprising, after treating said dyed fibers with said sodium nitrite solution, washing said dyed fibers in a sodium acetate solution.

3. The improvement as claimed in claim 1 wherein said sodium nitrite solution comprises from about 1 to about 5 grams of sodium nitrite per liter.

4. The improvement as claimed in claim 2 wherein said sodium nitrite solution comprises from about 1 to about 5 grams of sodium nitrite per liter.

5. In a process for the continuous dyeing of wool fibers which process comprises applying to said fibers an aqueous solution comprising Mordant Black 11, Color Index No. 14645, mineral or organic acid sufiicient to adjust to pH of said solution to below 5, chromic fluoride, and a dyestuif carrier comprising a solution of diethanolamine salt of the sulfated diglycol ether of lauryl alcohol, coconut oil fatty acid dihydroxyethyl amide, at a temperature below the drawing temperature of said Mordant Black Index No. 14645 dyestuif, steam fixing said dyestuif on said fibers, by reducing said chromic fluoride, and washing the dyed fibers, the improvement which comprises treating said dyed fibers after said steam fixing and before said washing, with an aqueous sodium nitrite solution, thereby improving the fastness of the dyed fibers.

6. The improvement claimed in claim comprising after treating said dyed fibers with said sodium nitrite solution, washing said dyed fibers in a sodium acetate solution.

7. The improvement as claimed in claim 5 wherein said sodium nitrite solution comprises from about 1 to about 5 grams of sodium nitrite per liter.

8. The improvement as claimed in claim 6 wherein said sodium nitrite solution comprises from about 1 to about 5 grams of sodium nitrite per liter.

9. In a process for the continuous dyeing of wool fibers which process comprises applying to said fibers an aqueous solution comprising Mordant Black 11, Color Index No. 14645 chrome dye, thickener, mineral or organic acid sufiicient to adjust the pH to from about 2 to about 5, chromic fluoride, and a dyestuff carrier comprising a solution of diethanolamine salt of the sulfated diglycol ether of lauryl alcohol, coconut oil fatty acid dihydroxyethyl amide, at a temperature below the drawing temperature of said Mordant Black 11, Color Index No. 14645, steam fixing said dye on said fibers, by reducing said chromic fluoride, and washing the dyed fibers, the improvement which comprises after said steam fixing, and before said washing, treating said dyed fibers with an aqueous sodium nitrite solution comprising from about 1 to about 5 grams per liter of sodium. nitrite, thereby improving the fastness of said dyed fibers.

10. The improvement as claimed in claim 9 comprising, after treating said fibers with said sodium nitrite solution, washing said dyed fibers in a sodium acetate solution.

11. An improved process for the continuous dyeing of wool fibers, which process comprises applying to said fibers an aqueous solution of Mordant Black 11, Color Index No. 14645; about 25 ml. per liter of a mixture of 10 parts of the diethanolamine salt of the unsulfated diglycol ether of lauryl alcohol, 9.1 parts of coconut oil fatty acid dihydroxyethyl amide, at a temperature below the drawing temperature of said Mordant Black 11, Color Index No. 14645, 25 ml. of formic acid, and 25 ml. of chromic fluoride; the balance Water per liter, steam fixing said dyestuff on said fibers by steaming said fibers for about 10 to about minutes to reduce said chromic compound, then treating said fibers with an aqueous solution comprising about 3 grams per liter of sodium nitrite at a temperature of about 160 F., washing said fibers in a solution containing about 3 grams per liter of sodium acetate and finally washing said dyed fibers in water, thereby improving the fastness of said dyed fibers.

References Cited UNITED STATES PATENTS 615,232 12/1898 Alt et al. 830 2,991,144 7/1961 Sandilands et al. 830X 3,178,253 4/ 1965 Hirshfeld 8--30X FOREIGN PATENTS 1,000,054 1 8/1965 Great Britain 887 GEORGE F. LESMES, Primary Examiner P. C. IVES, Assistant Examiner US. Cl. X.R. 830, 43, 88, 

